1. Field of the Invention
The present invention relates generally to a method for determining elemental contents of samples, and more particularly, the present invention relates to a method for using a solution cathode glow discharge for elemental analysis of samples.
2. Background of the Invention.
Elemental analyses of samples are critical in scientific endeavors of all fields.
Current approaches in elemental analysis rely on recording atomic emissions and analyzing same using a spectrometer. A common approach is to generate a small volume of plasma, and these forms of analysis have been in use in laboratories for many years.
Typical minimum sample volumes are at least 25 μl. As such, state of the art systems are not suitable for analyzing samples extracted from separations, such as by capillary electrophoresis or high performance liquid chromatography which typically yield samples below the minimum threshold levels of prior art approaches.
For example, U.S. Pat. No. 6,852,969 to Marcus, et. al., discloses a system for elemental analysis of a sample relying on glow discharge spectroscopy. However, the device disclosed by this patent relies on electric conductivity of conduits (element 25 in FIG. 1b) which transport analyte. Furthermore, prior art systems, such as the one disclosed by Marcus, generally introduce gas into the system, and therefore into the results of the elemental analysis.
A need exists in the art for a method that facilitates elemental analysis of samples with minimal inter-element interferences and high sensitivity. The method should also require only modest amounts of power and use instruments which are relatively simple, and require no gas flow. Finally, such a method should be applicable to sample sizes containing as little as 25 μl of analyte. The total solution flow rate, which includes the sample, carrier, and an optional supplemental stream should be no higher than 3.0 mL/min.